Majlesi Journal of Telecommunication Devices
Volume:9 Issue: 4, Dec 2020

One of the most important components in telecommunication systems and radar activities are frequency synthesizers. Among the important parameters of a frequency synthesizer are phase noise, frequency resolution, programming speed, scanning rate and spur level in the output spectrum of the system. Typically, it is not possible for a frequency synthesizer to reach all of these parameters simultaneously. In other words, there are trade-offs between desired parameters. Among the structures of frequency synthesizers that can be used to achieve the optimal point for these parameters are multi-loop phase lock loop. In this paper, by presenting the noise model of different elements of a frequency synthesizer, simulations related to the achievable phase noise for a sample synthesizer in the X band are presented and finally the results of implementation of a sample synthesizer are presented.

Electrocardiogram (ECG) signals play a crucial role in determining heart disease. Somehow, by knowing the heart rate on the ECG, one can distinguish the type of arrhythmia and the type of disease. Arrhythmias are a type of heart disease that affects the normal functioning of the heart. The electrical activity of the heart is shown at the peaks of P, QRS, T, and the ST and PR sections. In this study, an effective method for identifying cardiac arrhythmias based on morphological features is presented. The extracted features are classified using SVM and KNN classification and random forest RF. Accuracy, sensitivity, positive predictive rate, negative predictive rate as well as execution time were used to evaluate the proposed method. The results show the superiority of the proposed method.

This paper represents advantages of using Centroid distance function for shape detection in real time traffic sign recognition compared with extracting histogram of oriented gradients (HOG) features and using support vector machine (SVM) classifier. Simulation results of using centroid distance show similar accuracy in compare with HOG SVM while have very low complexity and cost and running with higher speed.

Many diseases cause death in people around the world. One of them is cancer, and many types of cancer diseases are seen today. One of the cancer types that cause the most death is Breast Cancer. Early diagnosis has an essential place in Breast Cancer as it is crucial in every disease. Thanks to early diagnosis, the patient's survival rate increases as a result of the treatment applied. Today, many studies are carried out and developed to be able to diagnose breast cancer early. The work done with the algorithms found in machine learning is just one example. In this paper, MLP (Multilayer Perceptron), which is one of the Machine Learning methods, and the algorithm in Breast Cancer Diagnosis is explained using the data collected in the Department of General Surgery, University Wisconsin, Center of Clinical Sciences.

This paper presents an analytical solution to the problem of non-invasively detecting an object in a medium using a microwave signal applied from the surface. This solution is based on the one and two-dimensional microwave inverse calculation methods. Since the dielectric properties of the object and the medium are different from each other, the backscattered electromagnetic waves can characterize the properties of the object and the medium. The impedance and reflection coefficients are calculated from the forward and backscattered signals as a function of the frequency. An analytical-numerical method is developed to analyze how an H-polarized plane wave is diffracting from two axisymmetric infinitely long strips located at the z-axis and have the same width. A straightforward solution to a problem difficult to solve is presented using hybrid analytical-numeric methods. Detecting tumors in breast tissue is one of the critical areas that the method will be effectively used. The solution is successfully applied to the breast tissue to detect the tumor inside it. Different scenarios are presented along with their numerical examples and radar cross-section data. From the insight obtained from these numerical examples, the scattering characteristics of the far-field are discussed to emphasize the contribution of the presented solution. 

FM bandwidth Modulation is an important parameter in voltage-controlled oscillators. The importance of this parameter is especially evident in cases in which the loop bandwidth of phase locked loops is comparable with the FM bandwidth of the oscillator. In this paper, a practical method for measuring the FM bandwidth of a voltage-controlled oscillator is presented.